FIREFIGHTING IN COVERED MALLS, PART 1
Photo by Fred Zwicky.
A serious fire in an enclosed shopping mall will challenge the resources of most fire departments and those of neighboring departments. Some have called the covered mall a “horizontal high-rise.” Multiwinged structures with long, large, open corridors, hundreds of storefronts, many locked gates, and the possible evacuation of thousands of shoppers are problems that first-arriving units may encounter. Just navigating apparatus through jammed parking lots to access mall entrances or sprinkler Siameses may be impossible during peak business hours.
Today’s “megamalls” may contain every thing from ice skating rinks to amusement parks, complete with ferris wheels and carousels. Malls may temporarily house yachts and automobiles —and even fire apparatus during Fire Prevention Week. The concourse may be crowded with kiosks and carts filled with wares. The new er malls may be protected by automatic sprinklers, a smoke-detection system, a smoke-removal system, and a standpipe system—but do not let these systems lull you into a false sense of security: Large, difficult fires have occurred in well-protected malls.
CONSTRUCTION
Due to the need for large, unobstructed sales areas and open assembly areas, truss construction is used a great deal. The newer malls normally are of steel-frame construction with lightweight steel bar trusses, but wooden trusses or laminated beams may be encountered in malls that have been renovated, enlarged, or converted from an open to a covered mall. Just as is the case with heavy timber truss, lightweight trusses are only as strong as their weakest member or connection. These truss assemblies are used to support additional floors as well as the roof deck. Roofs on large stores may be constructed of many different materials, including concrete planks, Q-decking (metal sheets) covered by insulation, and even tongue-and-groove boards. All roofs are covered by some type of waterproof covering, such as tar and gravel. It is not uncommon to find a large roof area, usually over a center court, made entirely of glass. One mall in upstate New York even has a roof made of waterproof fabric stretched over a steel tube frame that covers a pedestrian walkway.
Ventilation of concrete or metal roofs will be difficult because the common carbide-tip blade on power saw’s is ineffective on such construction. Employ all natural or engineered means of ventilation first—skylights, ventilators, and other available rooftop openings. Some malls, particularly newer ones, contain smoke-removal systems. Building codes require identification and accessibility of this system for the fire department. Gain control of this system and the HVAC system as soon as possible. Preplanning is essential —at the height of a fire is not the time to become familiar with an air-handling system. (See “Fire Protection in Covered Malls,” Fire Engineering, M arch 1991.)
Individual stores throughout the mall usually are separated by drvwallover-metal stud walls. Drop ceilings are common. Usually the walls extend in height only to the level of the drop ceiling, leaving a large void that may extend over many stores. This void may or may not be sprinklered. Utilities, including water lines, electrical wires, and heat and ventilation ductwork, are located in this space. Fire separations may have been required at certain intervals between stores; these separations usually are constructed of concrete blocks and extend from the first floor to the roof.
Occasionally, a store will leave the trusses and underside of the roof decking exposed (no ceiling) for decorative purposes, leaving the roof (or floor/ ceiling assembly if a second floor is present) with no protection from a fire unless structural members are given a special fire coating (fireproofing). Unprotected steel bar truss assemblies afford little, if any, time to work above them in a fire situation.
Individual stores have their own security devices, ranging from simple aluminum-frame doors with a one-key lock to rolldown gates with casehardened locks. Heavy smoke conditions with zero visibility make forcible entry for even a simple door/lock assembly a real problem.
Most stores have a rear entrance leading to a service corridor that serves all the stores in a section, but sometimes rear doors lead to the exterior. These doors, which may be heavily secured, need to be opened for horizontal ventilation as well as for an additional means of egress.
Be aw^are that some occupancies, particularly restaurants, may contain range hoods and ductwork that vent through an upper floor, providing an easy path for fire extension. Some occupancies also may have dumbwaiters, used to move food or supplies, that cover more than one floor.
ENGINE OPERATIONS
“Ladder l to Chief 3, we have very heavy smoke in the middle con- course, and sprinklers are discharging. ”
Ladder l calls for a hand line due to the heat and smoke members have found. As they advance, Engine 1 and Ladder 1 find a 20-foot-long mobile home on fire in the middle concourse. It is in the mall for the annual travel and outdoor show. Fire is burning furiously within the vehicle, but discharging sprinkler heads seem to be keeping the fire from extending beyond it. The neighboring department is on the way, and additional mutual aid is requested.
One of the first problems companies will encounter at a mall fire is traffic—getting close to a mall is difficult when perhaps thousands of people and cars are leaving. If there is a small or remote fire or emergency, it will be nearly impossible to get crowds to cooperate with responding units. Picture a fire on Saturday, December 22, at your local mall. Some people would rather burn up than leave without that last gift.
(Photos by Glenn Corbett.)
Water supply should be preplanned. The fire department should have input when the area is developed to ensure an adequate water supply and distribution system. Unfortunately, some shopping centers have been built with less than adequate water systems on the grounds. Even if the hydrants on the property supply sufficient flow, they may be on the same main that supplies the sprinkler system; using these hydrants may take critical water from the sprinklers. In such cases, large-diameter hose is critical in moving water from beyond the confines of the property.
Supply the automatic suppression system immediately. Finding the actual seat of the fire in a structure of this size may be difficult, and positioning the first handline may take considerable time. First water goes to the sprinklers, not a handline. Sprinkler riser locations and the area each riser covers must be preplanned (a mall may contain more than 20 risers). I)o not shut off the sprinklers until you have determined the fire’s perimeter and the first line is in operation on the main body of fire—well on its way toward knockdown. With the sprinkler system in operation, the smoke condition will be severe and some firefighters may be tempted to shut down the sprinklers to increase visibility and minimize water damage; but remember: Shutting off the sprinklers prematurely has led to the destruction of many buildings, as hidden fire rapidly spread into unburned parts of the structures. If the system is to be turned off, a radio-equipped fire officer should remain at the sprinkler valve to reopen the valves should unforeseen problems develop.
The first handline stretched into a shopping mall should be a 2‘/Hnch line — do not underestimate the potential for a mall fire to grow rapidly. The first stretch is no time to discover you don’t have enough fire power. Stretches may be extremely long, even with a standpipe system (national building codes require a standpipe system for covered malls), and personnel from more than one engine company most likely will be needed to get the first line into position.
Photos by Glenn Corbett.)
Stretching through the right mall entrance (generally the one closest to the fire) is essential. This demands a knowledge of fire location. Although searching for the seat of the fire without the protection of a hoseline is hazardous, the size of these malls makes this almost a necessity. The engine officer must use all the information he can gather from the exterior of the mall (from members, mall personnel and occupants, and radio reports) in an effort to pick the right entrance.
The use of a smooth-bore tip on handlines is desirable. The long stretches or standpipe stretches can cause friction loss problems resulting in having less than the 100 psi needed by automatic and standard fog nozzles. The need for reach and penetration into the store from the concourse also dictates the solid stream. Remember, the mall’s physical dimensions and design—large, open passageway and assembly areas with extensive concealed voids and wide, open store entrances (“see-through” gates)—encourage extensive fire development if left unchecked. If sprinklers are improperly maintained or designed or if the fire load (stock) has increased since sprinkler installation, thereby exceeding the system’s capabilities, you can have a fire involving a very large area. Big water is needed for this type of fire condition. If the fire is small, the 2½ can be wved to smaller handlines.
(Photos by Glenn Corbett.)
Numerous handlines are needed for a fire involving one store: a handline to back up the first line, a line for each adjoining store, and even lines for the stores above if the mall is more than one level. Fire may extend via autoexposure to the level above and across the concourse to stores on the other side of the mall. A large-diameter manifold may be useful to get additional handlines in operation. Placing the manifold in the concourse near the fire or near a stairway to an upper floor may make for a much smoother operation. Consider the use of hose packs to facilitate getting additional handlines into operation quickly.
(Photo by Fred Zwicky.)
For a heavy fire in a mall, a portable deck pipe or monitor may provide more knockdown potential. The newer-style lightweight units can be set up inside a structure. A largediameter line or multiple 2 ½or three-inch lines can be used to feed the monitor. One department has modified a Dodge Power Wagon to carry numerous lengths of five-inch hose and three deck guns. The principal intended use for this rig is a new mall; if necessary, members can drive it into the building.
The configuration of a mall, with its center pedestrian walkways, makes it essential to exercise great caution to avoid opposing hose streams during fire attack. If a fire has possession of more than one store in the middle of a mall, it may be necessary to attack from two directions to stop the fire spread. Communications will be the greatest aid to keep the crews from opposing and endangering each other. Crews should be aware of the locations of other operating units so they can direct their streams accordingly. This communication has to be constantly updated as conditions and operations change.
More in Part 2.